Update all references in core, plugins, and tests to import UserError
from the new location. This centralizes exception handling and improves
code organization.
tricky...
- the only way I found to express the concept of the "associated type"
(in Rust lingo) model_type was by making Type generic over its value
and null types.
- in addition, the class hierarchy of Integer and Float types had to be
modified, since previously some of them would have conflicting null
types relative to their super class (this required a change to the
edit plugin; hopefully no more breakage is caused by these changes)
- don't import the query module, but only the relevant Query's to avoid
confusing the module query and the class variable query
This works around a bug that does not exist in Python 3.x, and the
workaround (by calling the underlying shlex.split function with bytes)
was causing crashes on some versions of Python 3. Seemed to work fine on
3.10-dev, though, oddly.
Previously, if continuing to edit (i.e. invoking the $EDITOR) multiple
times in one invocation of EditPlugin.edit_objects, the plugin would
reload the old state from the file tags. The initial 'old state' is
usually only loaded from the database, though. As a consequence, if
database and tags were not in sync, the diffs from first and all
subsequent edits could differ unexpectedly.
* Revert the changes related to allowing the album- and item-level
fields to be edited at the same time, as the increase in complexity
was deemed excesive during review.
* Modify the interactive execution so temporary Item.id's are used,
removing the extra functionality needed for dealing with both id and
path as reference fields.
* Docstrings and comments cleanup.
* Add support for editing both the item fields and the album fields in
a single YAML file, by appending an Album-like object as the front of
the objects to be edited.
* The FakeAlbum class provides that object, mimicking the original
Album behaviour and including an _apply_changes() method that propagates
the changes read from the yaml onto the Items.
* Modify edit_objects() so the flattening of the objects takes into
account the type of object, using different fields for Albums and for
Items.
* Renamed apply() to apply_() to prevent an IDE warning about reusing a
reserved built-in symbol.
